Plug-in control switch



Dec. 11, 1956 D. F. MOYER PLUG-IN CONTROL SWITCH Filed Jan. 4, 1954 Fig. 3 l2 2e. 24 3330:@{254 l5-`z .VH/7| INVENTOR. ,om :H7 David F. Moyer VJ 27) "30 M t@ 24F/fg. 4 25 w@ W His Attorney United States PatentO PLUG-IN CONTROL SWITCH David F. Moyer, Dayton, Ohio, assignor to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application January 4, 1954, Serial No. 401,899

6 Claims. (Cl. 20D-115.5)

This invention relates to a control switch and particularly to a control switch that is adapted for plug-in insertion into a standard female electric plug receptacle.

There are control circuits in which at times it is desirable to insert a control switch to make and break circuit to an electrical apparatus. At other times it is desirable that the control switch be removed from circuit and a shunt connection be provided to arrange for continuous operation of the electrical device.

Under such conditions it is desirable to have the electrical device that is to be controlled connected with a standard plug-in receptacle so that either the control switch or the shunt element can be used in the control circuit. Also, it is desirable that various types of control switches be inserted into a control circuit according to the particular demands of the electric circuit to be controlled. Under these conditions it is desirable to utilize the standard electric female plug-in receptacle as the connection box or junction box to receive control switches having various characteristics interchangeable so that the characteristics of the contro-l circuit can be varied or changed at will. This is particularly true in those control circuits where thermally responsive elements are provided to effect breaking of electric circuit to the electrically controlled device in response to current surge to the electrical device, or in response to ambient temperature conditions.

It is therefore an object of this invention to provide an inexpensive plug-in control switch arranged to have a pair of male prong ends adapted for insertion into a standard female electric plug receptacle.

More specifically it is an object of the invention to provi-de a plug-in control switch that is not substantially larger than a standard male plug with the control switch located between the pair of prongs that extend from the plug.

A still further object of the invention is to provide a plug-in control .sw-itch to accomplish the foregoing objects wherein the switch itself is av thermally responsive element that may be actuated either in response to ow of current through the device or may be actuated by changing ambient temperature conditions.

Further objects and advantages of the present invention will be apparent from the following description, reference being had to the accompanying drawings wherein a preferred form of the invention is clearly shown.

ln the drawings:

Figure 1 is a plan view of the plug-incontrol switch of this invention.

VFigure 2 is a side elevational view of the control switch illustrated in'Figure 1.

Figure 3 is a cross sectional View taken along line 3 3 of Figure 2.

Figure 4 is a cross sectional view taken along line 4 4 of Figure 2.

ln this invention the plug-in control switch comprises a pair of metal prongs and 11 that are disposed in parallel relationship. The prongs 10 and 11 are adapted to provide male prong ends of a male electric plug and are adapted for insertion into a standard female electric plug receptacle. Thus the spacing between the parallel prongs 10 and 11 is the standard spac ing provided for male prong ends of an electric plug. Also, the width of the prongs 10 and 11 is that of the width of standard male prongs of an electric plug.

An electric circuit control switch 12 is adapted to be positioned between the prongs 10 and 11 and extends longitudinally parallel with the prongs 10 and 11.

The control switch 12 comprises a hollow body 13 made of electrical insulating material. The opening 14 within the body 13 receives a bimetal thermal control element 15 that has an electric contact 16 on the free end thereof. A stationary current conducting member 17 lays against one wall of the opening 14 and has the contact end 18 engaged by the contact 16 on the movable bimetal element 15. The conducting strip 17 and the bimetal element 15 are retained within the electrical insulating housing 13 by means of an electrical insulating plug 19 that forces the members 15 and 17 against opposite walls of the opening 14 within the body 13.

The bimetal member 15 has an electrical terminal tab 2t) extending from the body 13. Similarly, the ccnductin-g strip 17 has an electric terminal tab 21 extending from the body 13. These terminal tabs 20 and 21 are preferably disposed in parallel relationship.

The control switch 12 just described is like that disclosed and described in my copending application for patent, Serial Number 378,555 filed September 4, 1953, now Patent No. 2,743,335. This control switch 12 is adapted to open at a predetermined ambient temperature condition, or it can be adjusted to open in response toa predetermined current flow through the bimetal member 15. Either temperature condition will cause the bimetal 15 to deflect to open and close electric circuit.

The terminal tabs 20 and 21 are each connected to' one of the prongs 10 and 11 respectively, thereby retaining the control switch longitudinally parallel with the prongs 10 and 11 and between the same.

The prong 1t) has a plurality of ears 24 extend-insg from each of opposite edges thereof that are in the plane of the prong 10. Similarly, prong 11 has a corresponding number of ears 25 extending from opposite edges thereof in the plane of the prong 11.

The ears 24 and 25 extend through openings provided in electrical insulating sheets 26 and 27 that form a sheath around the prong and switch assembly. After the sheets 26 and 27 are assembled upon the prongs 10 and 11 the sheets being in parallel relation engaging opposite edges of the prongs 1li and 117 the ears 24 and 25 are deformed relative to the prongs 10 and 11 and relative to the openings in the sheets 26 and 27 through which the ears extend, as illustrated in Figure 4, whereby to secure the sheets-to opposite edges of the prongs 10 and 11 and thereby for-rn a sheath around the control switch 12.

The sheets 26 and 27 extend transversely beyond the switch and prong assembly, as illustrated in Figures l and 3, and extends beyond one longitudinal end of the assembly a distance to prevent direct engagement of the sides of the prongs 10 and 11 by the lingers of a person holding the control switch. The forward ends ofI the prongs 10 and 11 project beyond one llongitudinal end shock by simultaneous contact with both prongs and 11.

While the form of embodiment of the invention as herein disclosed constitutes a preferred form, it is to be understood that other forms might be adopted as may come within the scope of the claims which follow.

What is claimed is as follows:

l. A plug-in control switch comprising, a pair of parallel extending prongs adapted for insertion into a standard female electric plug receptacle, a switch member having an insulating body enclosure confining a switch structure therein with a pair of electric connection terminal tabs projecting exteriorly of the body at one end thereof in parallel relation, said switch member being positioned between said prongs longitudinally parallel therewith with said terminal tabs each secured to one of said prongs at correspondingly adjacent ends thereof, and an insulating sheath around said prongs with the unattached opposite ends thereof projecting from the sheath for insertion into a female receptacle, each of said prongs including attachment tabs engaging said sheath to secure thereby said prongs in said sheath and retain thereby said switch member between said prongs within said sheath.

2. A plug-in control switch comprising, a pair of parallel extending prongs adapted for insertion into a standard female electric plug receptacle with the prong width and the prong spacing substantially uniform from end to end thereof, a switch member having an insulating body enclosure having a width not greater than the width of said prongs and a depth not greater than the distance between said prongs confining a switch structure therein with a pair of electric connection terminal tabs projecting exteriorly of the body at one end thereof, said switch member being positioned between said prongs with said terminal tabs each secured to one of said prongs, and an insulating sheath around said prongs with the unattached ends thereof projecting from the sheath for insertion into a female receptacle.

3. A plug-in control switch comprising, a pair of parallel extending prongs adapted for insertion into a standard female electric plug receptacle with the prong width and the prong spacing substantially uniform from end to end thereof, a switch member having an insulating body enclosure having a width not greater than the width of said prongs and a depth not greater than the distance between said prongs confining a switch structure therein with a pair of electric connection terminal tabs projecting exteriorly of the body at one end thereof in parallel relation, said switch member being positioned between said prongs longitudinally parallel therewith with said terminal tabs each secured to one of said prongs at corresponding ends thereof, and an insulating sheath around said prongs with the unattached opposite ends thereof projecting from the sheath for insertion into a standard female electric plug receptacle.

4. A plug-in control switch comprising, a pair of parallel extending prongs for insertion into a standard female electric plug receptacle, said prongs each having ears projecting from opposite edges thereof, a switch member having an insulating body enclosure confining a switch structure therein with a pair of electric connection terminal tabs projecting exteriorly of the body at one end thereof, said switch member being positioned between said prongs with said terminal tabs each secured to one of said prongs, and an insulating sheath around said prongs with the unattached ends thereof projecting from the sheath for insertion into a female receptacle, said ears projecting through said sheath and deformed relative to 4 said prongs and relative to said sheath to secure thereby said prongs in said sheath.

5. A plug-in control switch comprising a pair of parallel extending prongs for insertion into a standard female electric plug receptacle, said prongs each having ears projecting from opposite edges thereof in the plane of the respective prongs, a switch member having insulating body enclosure coniining a switch structure therein with a pair of electric connection terminal tabs projecting exteriorly of the body at one end thereof, said switch member being positioned between said prongs with said terminal tabs each secured to one of said prongs, and an electrical insulating sheet engaging each of opposite edges of said prongs, said ears projecting through the respective sheet and deformed relative to said prongs and relative to said sheets whereby to secure said sheets on opposite edges of said prongs, said sheets projecting beyond the prong and switch assembly transversely thereof and longitudinally thereof at one end to electrically isolate the prongs from direct engagement by the fingers of a person holding the control switch, said prongs extending longitudinally be yond one end of said sheets to provide thereby male prong ends for insertion into a standard female electric plug receptacle.

6. A plug-in control switch comprising, a pair of parallel extending prongs for insertion into a standard female electric plug receptacle with the prong width and the prong spacing substantially uniform from end to end thereof, said prongs each having ears projecting from opposite edges thereof in the plane of the prongs, the switch member having an insulating body enclosure have ing a width not greater than the width of said prongs and a depth not greater than the distance between said prongs confining a switch structure therein with a pair of electric connection terminal tabs projecting exteriorly of the body at one end thereof in parallel relation, said switch member being positioned between said prongs longitudinally parallel therewith with said terminal tabs each secured to one of said prongs at correspondingly adjacent ends thereof, and an electrical insulating sheet on each of opposite edges of said prongs and engaging corresponding edges of the said prongs, said ears projecting through the respective sheets and deformed relative to said prongs and relative to the openings in said sheets through which said cars project whereby to secure said sheets upon said prong edges, said sheets projecting beyond the prong and switch assembly transversely thereof and longitudinally thereof at one end of the assembly to electrically isolate the prongs from direct engagement by the fingers of a person holding the control switch, said prongs extending longitudinally beyond one end of said sheets to provide thereby male prong ends for insertion into a standard female electric plug receptacle.

References Cited in the le of this patent UNITED STATES PATENTS 1,028,258 Murray June 4, 1912 1,798,174 Sheller Mar. 31, 1931 1,830,657 Herbster Nov. 3, 1931 1,851,144 Abramson Mar. 29, 1932 1,952,279 Peterson Mar. 27, 1934 2,209,583 Shaw July 30, 1940 2,222,291 Freeman et al Nov. 19, 1940 2,399,406 Toth Apr. 30, 1946 2,420,300 Cataldo et al. May 13, 1947 2,462,934 Athey Mar. l, 1949 2,587,789 Talmadge et al. Mar. 4, 1952 2,643,312 Rodden June 23, 1953 

